This invention relates in general to semiconductor wafer processing and in particular, to an apparatus and method for enhancing a stripping or etching step in the process wherein a layer or layers, or portions of a layer or layers of a semiconductor wafer are selectively stripped or etched away by an etching solution.
During batch processing of semiconductor wafers, selective stripping or etching away of a layer or portions of a layer or layers of the wafers is required. A conventional technique immerses a plurality of wafers into an etching solution, and then mechanically moves the plurality of wafers in an up/down and/or back/forth agitating motion to enhance the stripping or etching away process.
One problem with this technique is that the etching solution remains stagnant and eventually becomes saturated with stripped or etched away material near the wafer surfaces. Consequently, the stripping or etching process becomes less effective over time and eventually, the etching solution must be replaced.
Another problem is that a mechanical means for providing the up/down and/or back/forth agitation motion may be expensive, bulky and subject to mechanical break down. As a consequence, this may add to the processing cost of the wafers which would result in more expensive integrated circuits, and may increase the likelihood of line stoppages which would result in manufacturing delays.